Frequency of Allogeneic Hematopoietic Cell Transplantation Among High-Risk AML Patients in First Complete Remission at an Academic Center

Allogeneic hematopoietic cell transplantation (HCT) likely prolongs survival in high-risk adults with acute myeloid leukemia (AML) in first complete remission (CR1). Prior studies, however, suggest that only about 15% of AML patients age ≥50 with abnormal cytogenetics who entered CR1 at an academic cancer center received a reduced intensity HCT in CR1 (Estey et al., Blood 2007;109:1395-1400). In this study, only HLA-matched siblings were primarily used as donors, raising the question of the frequency with which HCT is performed in adults of all ages entering CR1 if unrelated donors as well as siblings are utilized. Here we address this question and compare high- or intermediate-risk AML patients who did and did not receive HCT while in CR1. Between Jan, 1 2008 and March 1, 2011, 244 patients received treatment for newly-diagnosed AML at our Center and who achieved CR or CRi [98/117 (84%) in CR and 19/117 (16%) in CRi]. Because HCT is generally not recommended/undertaken in patients age >75 or who have favorable cytogenetic risk [inversion 16, t(8,21), or t(15;17)] or who are NPM1 mutated and FLT3 wild-type, we excluded such patients, leaving 117 with high- or intermediate-risk AML in CR1. Logistic regression was used to distinguish characteristics associated with receiving HCT in CR1. Seventy-nine AML patients (68%; 95% CI 59-76%) received HCT in CR1 at a median of 5.1 months (range, 1.2-20 months) from their CR1 date. Characteristics of patients who received or did not receive HCT in CR1 are shown in the Table below:TableHCT vs No HCT in CR1HCT (79 pts)No HCT (38 pts)P-value logistic regressionMean Age (range)53 (18-75)55 (24-73)0.54Mean Performance status at CR1 (range)1.1 (1-2)1.5 (1-4)0.005Mean HCT-CI (range)1.7 (0-11)1.9 (0-7)0.65Unfavorable cytogenetics (n)30 (37%)7 (18%)0.18Secondary AML (n)39 (49%)15 (39%)0.32Early relapse (n) (>5% marrow blasts within 4.9 months of CR1 (range 0.9-10, median 3.75)0 (0%)13 (34%)<0.001 Open table in a new tab Twenty-four of the 38 (63%) non-HCT patients were HLA-typed and matched donors were found for 13 of these 24 patients (54%; 5 related, 8 unrelated). Seven of the 14 non-typed patients (50%) had financial barriers or refused HLA-typing. Only 2 of these 38 (5%) received HCT beyond CR1. These data suggest that HCT can be performed in CR1 in the majority of high-risk AML patients in whom it is currently recommended. Patients in whom HCT is not done are characterized by a poorer performance status (but not older age) and by early relapse. In the absence of these 2 factors, >75% of patients with high-risk AML under the age of 75 can receive HCT in CR1. A national study is planned to assess the extent to which these results can be generalized.